(1) With its unempowering, non-transformational spirituality, and widespread belief in a non-interventionist God, UCCan is in the steepest decline of any denomination:
broadview.org
(1a) Yet even in Canada, conservative churches, including conservative United Churches, are growing and thriving due to their lived experience of "the power of prayer" and their unambiguous acceptance of the authority and power of biblical application:
www.christianitytoday.com
(1b) Despite UCCan's steep decline except for its conservative churches, some UCCan liberal churches are thriving. Why? Among other factors, because of their stress on the experience of spiritual growth through spiritual formation, small groups, vibrant worship in which God is truly adored, and highly success children and youth programs:
www.winnipegfreepress.com
(2) By contrast, Roman Catholics increase their global number by a whopping 14 million in just one year (2 022):
www.catholicnewsagency.com
(3) Far more impressive still is global Pentecostalism, which sociologist Peter Berger characterizes as the fastest growing religious phenomenon in religious history:

The United Church's numbers have dropped more than any other denomination | Broadview Magazine
Canada's largest Protestant denomination is shrinking the fastest. The latest census paints a grim picture of The United Church of Canada, which lost a whopping 40 percent of affiliates between 2011 and 2021, falling to 1.2 million people from roughly two million.

(1a) Yet even in Canada, conservative churches, including conservative United Churches, are growing and thriving due to their lived experience of "the power of prayer" and their unambiguous acceptance of the authority and power of biblical application:

Even in Canada, Conservative Churches Are Growing - Christianity Today
Mainline churches with evangelical leanings outpace their liberal counterparts, study says.

(1b) Despite UCCan's steep decline except for its conservative churches, some UCCan liberal churches are thriving. Why? Among other factors, because of their stress on the experience of spiritual growth through spiritual formation, small groups, vibrant worship in which God is truly adored, and highly success children and youth programs:

Jan 2021: Thriving United Churches built on 'spiritual attributes'
Two years ago, Loraine MacKenzie Shepherd was feeling stuck. Since arriving of Westworth United Church in 2013, the minister had made a number of changes to its mission statement, governance structure...

(2) By contrast, Roman Catholics increase their global number by a whopping 14 million in just one year (2 022):

The Catholic Church by the numbers: more Catholics, fewer vocations
While vocations to the priesthood and religious life have decreased overall, the Church shows signs of growth in some parts of the world — most notably Africa and Asia.

(3) Far more impressive still is global Pentecostalism, which sociologist Peter Berger characterizes as the fastest growing religious phenomenon in religious history: